Two dimension radar system that backs a car based on ultrasonic ranging

The utility model discloses a two dimension radar system that backs a car based on ultrasonic ranging, this system include ultrasonic water flat range finder, ultrasonic wave ground monitor and singlechip, through the flat range finder of ultrasonic water to the first ultrasonic wave of horizontal direction transmission to receive the first echo of first ultrasonic wave corresponding to first barrier, angle direction transmission second ultrasonic wave is predetermine downwards to ultrasonic wave ground monitor syncline to receive the second echo of second ultrasonic wave corresponding to the second barrier, the singlechip utilizes first hyperacoustic transit time and the hyperacoustic transit time of second, calculates the distance that obtains between the rear of a vehicle and first barrier, the second barrier respectively to distance between the rear of a vehicle and first barrier is lighter than the distance of presetting between a safe distance and/or the rear of a vehicle and the second barrier and is lighter than when presetting the 2nd safe distance, and corresponding alarm signal is sent in control, and with the ground road conditions of reminding driver's automobile dead astern, so as to effectively improves driving safety.